The present invention relates to the adjustability of elongate frames of the type which have a generally open-sided construction making possible the loading of two or more tiers of vehicles onto the frame and which, after being loaded, are adapted for insertion into a standard cargo-carrying container for shipment.
Frames of the above type are shown, for example, in Gearin, et al. U.S. Pat. Nos. 4,768,916 and 4,797,049. A newer model of this type of frame is shown in Halpin, et al., U.S. patent application Ser. No. 784,902, filed Oct. 30, 1991. In each of these disclosures, the frame shown is of a generally open-sided box-like construction where each side of the frame includes a longitudinally-extending upper and lower rail. Both at the corners of the frame and at longitudinally-spaced positions therebetween, upright brace members are used to connect together the upper and lower rail. At the ends of the frame, the sides are connected together such as by a spreader bar or by a two-panel centrally-hinged gate that is capable of being folded inwardly in order to collapse the sides of the frame.
In order to support vehicles on the above-described type of frame, respective pairs of elongate wheel cradles are suspended across the respective sides of the frame to support the forward and rearward wheels of each vehicle. In particular, each end of each wheel cradle is supported by an end hanger which, in turn, is vertically slidable and adjustably lockable along a tension member suspended by its upper end from the upper rail of the frame. The vertical slidability of the end hangers makes possible power-assisted vertical lifting of each vehicle by the hangers. The upper ends of the respective tension members are, in turn, longitudinally movable along the upper rails in order to compensate for differences in vehicle wheel base as well as to allow tilting of the vehicles. An elongate plate having numerous openings or slots spaced therealong is affixed to the inward edge of each upper rail, each opening or slot providing a different pinning or locking position for each tension member.
A difficulty with the above-described type of frame relates to the differing sizes of the containers that are encountered at different vehicle loading and unloading stations. In particular, cargo-carrying containers that are 40 feet, 45 feet, and 48 feet in length may be encountered. The present frames of fixed dimension are required to have a length no longer than that which will fit within the shortest container. This presents the problem of preventing to-and-fro movement of these frames within the longer-length containers during transport. Furthermore, even if a movement-limiting mechanism is provided, there remains the problem of the reduction in the number of vehicles that might otherwise have been shipped in the longer-length container. For example, whereas normally only three larger-sized vehicles can be carried on the present frame which is 39 feet in length (suitable for a 40-foot container) if, instead, the frame were 47 feet in length (suitable for a 48-foot container) it might be possible to carry as many as six larger-sized vehicles.
In view of the above, there clearly exists a need for a vehicle-carrying frame which is adjustable in length. Unfortunately, due to the basic structure of the frame as well as its intended use, this objective has not been readily obtainable. A frame having adjustable wheel platforms is shown in Swartzwelder U.K. Patent No. 1,006,496, but this reference does not describe how to achieve extensible movement between entire ends of the frame where each end includes upper and lower rails joined by elongate brace members. In fact, such extensibility is not easy to implement, particularly between the upper rails of each end, because these upper rails must uniformly provide numerous locking positions for the tension members which support the wheel cradle end hangers. Furthermore, because the side-to-side spacing of one end would differ somewhat from the side-to-side spacing of the other end in a telescoping structure, wheel cradles of different widths would be needed in order to support vehicles on the frame.
Accordingly, the principal object of the present invention is to provide a vehicle-carrying frame having an improved mechanism for adapting to containers of varying length by enabling selective adjustment of the length of the frame.
A related object of the present invention is to provide a mechanism of the above type that, despite such adjustability in length, retains the ability to position its vehicle-supporting tension members longitudinally wherever they are needed.
Another related object of the present invention is to provide a mechanism of the above type that does not require the use of wheel cradles having different widths in order to support vehicles at different positions on the frame.
Yet another related object of the present invention is to provide a mechanism of the above type where the length can be adjusted without the need to add or subtract any frame sections.